1. Field of the Invention
The present invention relates to a spatula heating apparatus used for wax molding and adjustment for precision casting in the fields of dental prosthesis and metalwork with precision casting.
2. Description of the Related Art
A dental wax spatula is a tool for wax molding that is used to form and adjust casting models for dental crowns, denture bases or the like, using wax, in the process of simultaneously forming dental crowns and denture bases from dental alloys through precision casting such as lost-wax process. The wax spatula is frequently used for forming a wax model utilized for centrifugal casting of metalwork as well.
As shown in FIG. 13, a conventional spatula is formed with a metallic spatulate portion 102 which may take various shapes such as paddle-like, knife-like, lancer-like, or needle-like one at a distal portion of a grip stick 101. When using the conventional spatula, the spatulate portion 102 used to be repeatedly brought close to flame 105 of a touch burner 104 connected to an end of a gas pipe 103, with the grip stick 101 being held by a hand so that it may be heated by the touch burner 104 of a gas burner type, thereby using it for wax molding.
On the other hand, due to too evil stench emitted from wax at the time of heating by the aforementioned gas burner, an electro-thermal spatula heating apparatus is recently proposed as disclosed in, for example, Japanese un-examined patent publication No. 10-108872 or 2001-314421. As shown in FIG. 14, such spatula apparatus comprises, a spatula body 113 including a built-in electro-thermal body (not shown in the drawing) in a distal portion of a grip 112 with a spatulate portion 111 fixed thereto, a temperature regulator 115 connected to the spatula body 113 through a cord 114, and a foot switch 116. When the softening and melting temperatures of wax used are set in advance by operating respective adjusting dials 117, 118 of the temperature regulator 115 and then a power switch is turned on, the spatulate portion 111 is brought into a state where it is usable at a level of the wax melting temperature, while the temperature of the spatulate portion 111 is thereafter switched to either the wax melting temperature or the wax softening temperature every time the foot switch 116 is stepped on.
However, the electro-thermal spatula heating apparatus shown in FIG. 14 has the following problems. That is, users have had difficulties in performing wax molding work due to the hindrance by the cord 114 which is connected as a power wire to the grip 112. Further, the spatula body 113 has to be exclusively used for the very apparatus as the electro-thermal body is built in the spatula body 113, so that users"" favorite spatulas which have been used together with a gas burner cannot be used even in an apparatus to which several different types of the spatulate portions 111 are appended. Furthermore, as the spatulate portion 111 of a different shape is usually required for each of different wax molding works, troublesome replacement works for fixing a particular different type of the spatulate portion 111 relative to the temperature regulator 115 must be carried out ad hoc. Moreover, there is a problem that a spatula body equipped with a large-sized spatulate portion 111 for wax embanking works cannot be employed as the large-sized spatula needs too large an amount of heating to be fully heated, and a temperature sensor built in the grip 112 is unable to detect accurate temperature.
To eliminate the above-mentioned problems, it is, therefore, an object of the present invention to provide a spatula heating apparatus with excellent usability, by overcoming the drawbacks of the conventional gas burner type and electro-thermal type heating apparatus.
According to a spatula heating apparatus of the present invention, a spatula is heated through electromagnetic induction by feeding current to a heating coil. Hence, no exhaust gas nor exhaust heat is generated unlike the conventional gas burner type apparatus, thus reducing the loss of consumption energy to an extremely small value. Further, users can work safely due to the absence of open flames, while they suffer from less emission of an evil stench due to no smoke being generated from wax.
Further, a power wire such as a cord or the like need not be connected to a spatula itself, so that there is no such a nuisance accompanied with wax molding works as that in the electro-thermal type apparatuses. Furthermore, as such a small loss of consumption energy enables the easier heating of even large-sized spatulas, conventional spatulas inclusive of large-sized ones for wax embanking works can be used as they are without modifying them.
According to the spatula heating apparatus of the present invention, users can determine properly whether the heating of the spatula is ongoing or not through an information device such as a buzzer or the like.
Also, according to the spatula heating apparatus of the present invention, users can determine properly an electric power fed to the spatula through a display device.